Material feeding mechanism



MATERIAL FEEDING MECHANI SM Filed May 5, i955 Patented Sept. 25, 1934UNITED STATES PATENT oFFICE l 12 Claims.

VThis invention relates to a mechanism for use in feeding coal or otherfuel to furnaces, or other materials to other devices, and hasparticularV reference to a mechanism of this character in i which thefeeding element is in the form of a worm.

Mechanisms of the type in which a worm constitutes the feeding elementfor the fuel or other material are known and are in use. However,according to known mechanisms of this type the worm is, by rotation,caused to force the fuel or other material through a tube in which theworm is disposed, and this generates a great amount of friction on theworm and the tube. Consequently, considerable power is required tooperate such mechanisms even when reduction gears are employed betweenthe source of power and the worm, as is usually the case. Then too, thegears complicate the mechanisms and by their Vfriction also absorbconsiderable power, with the result that such mechanisms are of lowefficiency.

Accordingly, the present invention has generally in View to provide afeeding mechanism of the worm type for fuel and other material, whichmechanism embodies a construction and mode of operation whereby itsefficiency is materially increased as compared with known feedingmechanisms of the worm type.

More particularly the invention has in View to provide, in a feedingmechanism of the worm type, means whereby the worm is movedlongitudinally, without rotation, so as to act as a pusher or plunger toadvance or feed the fuel, and whereby the worm is returned to aretracted or starting position by rotation, these movements of the wormbeing produced alternately and automatically as long as the mechanism isin operation.

Another object of the invention is to provide a mechanism which has anovel mode of operation as stated and which includes novel means underthermostatic control whereby operation of the mechanism is initiated andstopped.

With the foregoing and other objects in view, which will becomemorefully apparent as the nature of the invention is better understood,the same consists in the novel features of construction, combination andarrangement of parts as will be hereinafter more fully described, illusu50 trated in the accompanying drawing and defined in the appendedclaims.

In thedrawingz- Figure 1 is a longitudinal section through the mechanismillustrating the status thereof upon advance of the worm and rotation ofthe worm and as the worm is about to be advanced without rotationthereof.

Figure 2 is a view similar to Fig. 1 illustrating the status of themechanism upon completion of is about to be initiated to y,effect itsretraction; and

Figure 3 is a fragmentary plan View illustrating the cam element of themechanism.

Referring in detail to the practical embodiment of the inventionillustrated in the drawing, 10 designates a fixed tube or casing whichis understood to lead to a furnace or other device to which fuel orother material is to be fed, 1l designates a hopper for the fuel orother ma- Vterial disposed to have the fuel or other mate-rial deliveredtherefrom into the tube or casing 10 through an opening 12 therein, and13 designates `a feeding element for the fuel or -other material whichelement is in the form of a worm mounted within the tube or casing 10for rotation and longitudinal movement relatively thereto.

At the outer end of the tube 10 is a housing 14 having an opening 15therein in axial alinement with the tube, and slidably and rotatablymounted in this opening .is a sleeve 16 which, at its inner end, issuitably secured to the worm 13, as by means of the elements 17, andwhich, at its outer end, has xed thereto the male element 18 of aconical clutch. 85 Slidably and rotatably mounted at its inner endwithin the outer end portion of the sleeve L16 is a shaft 19 which is ofsuitable length and which, at its outer end, is rotatably mounted withina cap element 20 which, in turn, is mounted for 90 longitudinal slidingmovement in a fixed element 21. The cap element 20 is suitably swiveledto the shaft 19 so that it is movable inwardly with the shaft and sothat the shaft cannot move longitudinally outwardly with respectthereto, 95 and preferably, but notA necessarily, said cap element issuitably held against rotation within the element 21.

AFixed to the shaft 19 outwardly of the clutch element 18 and inwardly-of the element 21 is'a lo() worm wheel 22 with which meshes a drivingworm V23 deriving'its power from any suitable source such, for example,as an electric motor'l (not shown) At its inner side, the worm wheel 22carries the female element 24 of the aforementioned 105 cone clutch,while between said wormwheel and the male clutch element 18 isinterposed an eX- pansion spring 25 of preferably helical form whichtends constantly to move the worm wheel Completion of retractleAmovernentl of the worm and the male clutch element relatively apart Vand4110 to engage the said male clutch element with the female clutchelement 24, thus to couple the worm wheel and the fuel feeding elementor worm 13 for unitary rotation.

Carried by the element 21 and facing the outer side of the worm wheel 22are two duplicate, substantially semi-circular cam tracks 26 havingsubstantially diametrically opposed high and low points 26a and 2Gb,respective-ly, whicnare spaced longitudinally ofthe mechanism, eachtrack eX- tending circumferentially at a gradual inclination from itslow point to its high point.

Mounted loosely on the shaft 19, between the l worm wheel 22 and theelementZl, isa member 27 having diametrically opposed pins 28 on whichare journalled rollers 29 which operate between the cam tracks 26 andthe adjacent* side of the worm wheel 22.

Carried by the cap element 2f) at the inner end thereof is a laterallyprojecting flange 30 having an inwardly beveled edge, while' mounted inthe element 21 for inward and outward lmoven'ient relative to the shaft19 and for cooperation with the llange 30, is a thermostatically orotherwise `controlled stop member 31. Y

As the actuating means for the stop member 3l Amay be of any suitabletype and does not, in itself, form part of the invention, it has notbeen illustrated. On the contrary, it is sufficient to say that, whenthe mechanism is used for feeding fuel to a furnace and when a desiredtemperature of the ,house or other enclosure to be heated has beenattained, the control means for the stop element 3lv operates to movesaid member in- `wardly to the position shown in dotted lines in Fig.1and in full lines in Fig. 2, and that when .thetemperature falls' belowa predetermined degree, thecontrol.means operates to move said stop,member outwardly to the full line position yshown in Fig, 1 and to holdit in this position.

Alternatively, ifthe mechanism is used vfor feed- .ingsome materialother than fuel, any suitable means, operable in response to the feeding:of a greateror alesser amount of the material than ,has-beenpredetermined asibeing desirable, may

be -employed toactuate the stop element 3l.

Assuming that the stop element 31 is held in its --outer position, theoperation of the mechanism is as follows: The driving worm 23 rotatestheworm wheel 22and with it the female clutch element 24., With theparts inthe relative positionsshowndn Fig. 1;A that is, with the rollers29 engaging .thelow points 26b ofthe cam tracks andthe material feedingworm 13 in its retracted position, and inward longitudinal or materialadvancing movement thereof resisted by the material, :rotation of theworm wheel 22 results in rotation of the rollers 29 about their pins 28.As the rollers thus rotate they roll against and climb ,up thecam tracks26, and since `the cam tracks arefxed, this climbing ofthe rollersresults in the worm wheel 22 being pushed inwardly or, as illustratedginlFig. '1, in; a right handdirection.

,As soon asinward movement of the worm wheel 22; is initiated,compression of the spring 25 ag-ainstthe'restrained malev clutchelementl 18 fis initiated .and ,the female clutch elementV is moved`inwardlyy relativelyto the male clutch element,

thereby disengaging the clutch sothat rotation ofthe VwormV wheel 22 isnot imparted to the feed 'worm 13. Upon continued-inward movement of theworm-wheel 22 Vthe spring 25 soon is fully compressed and then acts as apositive compression element between said wormwheel Vand theextensionliefor operating-an ash conveyor. Also,

-ride .over said high points outward movement of sleeve 16, asillustrated in Fig. 2, so that upon further inward movement of the wormwheel the feed worm 13, due to its connection with the sleeve 16, isforced longitudinally inward and thereby is caused to act as a piston orplunger to advance the material through the tube 10. When finally therollers 29 reach the high points 26iL of the cams the inward or fuelfeeding stroke of the worm 1S is completed, and when the rollers rideover the cam high points 26a and are no longer restrained againstoutward movement, the spring 25 immediately expands and, reacting fromthe male clutch element 18, moves the worm wheel 22 outward, therebycausing engagement of the female clutch element with said male clutchelement and coupling the worm wheel 22 and the feeding worm 13 forunitary rotation. The direction of rotation of the worm wheel and thefeed- -ing worm is such as to unscrew the latter from the material whichhas been advanced. Consejquently, continued rotation of the worm wheelresults in rotatable'retraotile movement of the feeding worm and, ofcourse, axial outward movement of the worm wheel. When the rollers 29ride" over thehigh points of the cams 26 and thereby are 100 'movementof the'feedingworm. Thereupon, continued rotation results in the rollersagain beginning to climbthe cam tracks with'the result lofflrst'disengaging the clutch-andimmediately thereafterinitiatingnon-rotative advance orinward pushing movement of the feeding worm aspreviously explained. Obviously, as long as the'115 stop member' 31 ismaintained retracted and the driving worm 23 continues to turn theoperations recounted are repeated and intermittent feeding of the fuelor other material is effected. On the Y.

other hand, if,.during operation of the mechanism, the. stop member 3lis moved inwardly,

feeding operationof the mechanism is .stopped geven though the worm 23,may continue Ato drive ythe worm wheel 22. `stopfmember 31 is movedto`its inner position Vit is disposed in the path of longitudinal move-That is to say,.when.the125 mentof the flange 30 of the cap `element 20,so

that when Ysaid .cap element moves inwardly with the shaft 19, 4theilange Sondes across said stop member and-momentarily forces the sameout-V wardly, 'whereupon the stop member drops or is projected behindsaid flange. This occurs just prior to the rollers .29 reaching the highpoints 26a of they-cams 26, so that when the rollers 29 135 the shaft-19and, consequently, of the worm wheel 22, is prevented. The spring 25then cannot eX- 'pand to .engagexthe clutchelements and asga re- When,'however, the stop member 31 subsequently is withdrawn from behindtheflangeBO, the spring 25 is permitted to-v expand to engage thel clutchand operation `of the mechanism again is initiated with unscrewing ofthefeeding worm from thematerial.

The motor for driving the` worm 23 may operate'` continuously in `orderto continuously rotate the shaft 19 whiohhas splined thereto a shaft.150

air may be fed through the housing 14 and the worm 13 to promotecombustion in the furnace.

Without further description it is thought that the features andadvantages of the invention will be readily apparent to those skilled inthe art, and it will of course be understood that changes in the form,proportion and minor details of construction may be resorted to, withoutdeparting from the spirit of the invention and scope of the appendedclaims.

I claimtl. A material feeding mechanism comprising a material feedingelement, a motor driven rotatable power element, cam means operated bysaid power element to move said feeding element longitudinally andnon-rotatably to advance the material slowly, and clutch means forconnecting said feeding element with the motor driven rotatable powerelement thereby to rotate said feeding element and effect its retractionquickly.

2. A material feeding mechanism comprising a material feeding element, arotatable power element, and means operable in response to contin- `dousrotation of said power element to alternately move said feeding elementlongitudinally nonrotatively to advance the material and to rotate saidfeeding element to effect its retraction.

3. A material feeding mechanism comprising a material feeding element, arotatable power element, means operable by said power element to movesaid feeding element longitudinally to advance the material, a clutchbetween said power element and said feeding element, means to disengagesaid clutch when material advancing longitudinal movement of the feedingelement is initiated, and means to engage said clutch upon completion ofsuch movement of said feeding element.

4. A material feeding mechanism comprising a material feeding element, arotatable power element, cam means operable by said power element tomove said feeding element longitudinally to advance the material, aclutch between said power element and said feeding element, means todisengage said clutch when material advancing longitudinal movement ofthe feeding element is initiated, and means l,o engage said clutch uponcompletion of such movement of said feeding element.

5. A material feeding mechanism comprising a material feeding element, arotatable power element, means operable in response to continuousrotation of said power element to alternately move said feeding elementlongitudinally to advance the material and to rotate said feedingelement to effect its retraction, and means operable to render themechanism inoperative while the power element continues to rotate andwithout disturbing the driving connection between the power element vandthe mechanism.

6. A material feeding mechanism comprising a material feeding worm, aclutch element'aflixed thereto, a power driven wheel, a clutch elementcarried by said wheel for cooperation with said first mentioned clutchelement, spring means tending constantly to shift said wheel axially ina direction to effect engagement of said clutch elements, means wherebyaxial movement of said wheel in an opposite direction effectsdisengage-v ment of said clutch elements and longitudinal materialfeeding movement of said worm, and cani and cam follower means renderedeffective in response to rotation of said wheel to move the latter inthe last mentioned axial direction and subsequently to permit saidspring means to act to shift said wheel to engage the clutch elementsand to permit resulting retractile rotative and longitudinal movement ofthe feeding worm.

7. A material feeding mechanism as set forth in claim 6 including stopmeans to prevent axial movement of the power wheel in the rst mentioneddirection whereby the clutch is maintained disengaged.

8. A material feeding mechanism comprising a rotatable and axiallymovable material feeding worm, a coaxial rotatable power driven wheel, a

` clutch element ailixed to the worm, a cooperating clutch elementcarried by said wheel, spring means tending constantly to shift saidwheel axially outward to effect engagement of said clutch elements,fixed cam means outwardly of said wheel, and rollers between said cammeans and said wheel cooperating therewith in response to rotation ofthe wheel to move the wheel inwardly to disengage the clutch andYsubsequently to force the feeding worm inwardly.

9. A material feeding mechanism comprising a rotatable and axiallymovable feeding worm, a sleeve extending outwardly from the outer end ofthe feeding worm, a male conical clutch element affixed to said sleeve,a shaft having its inner end journaled in said sleeve, a power drivenwheel affixed to said shaft outwardly of said male clutch element, afemale conical clutch element carried by said wheel, a spring betweensaid male clutch element and said wheel tending constantly to move thewheel axially outward to eect engagement of the clutch elements, fixedcam means outwardly of said wheel, and rollers between said cam meansand said wheel cooperating therewith in response to rotation of thewheel to move the f wheel inwardly to disengage the clutch andsubsequently to force the feeding worm inwardly.

i0. A material feeding mechanism comprising a rotatable and axiallymovable feeding worm, a sleeve extending outwardly from the outer end ofthe feeding worm, a male conical clutch element affixed to said sleeve,a shaft having its inner end journaled in said sleeve, a power drivenwheel affixed to said shaft outwardly of said male clutch element, afemale conical clutch element carried by said wheel, arspring betweensaid male clutch element and said wheel tending constantly to move thewheel axially outward to effect engagement of the clutch elements, fixedcam means outwardly of said wheel, rollers between said cam means andsaid wheel cooperating therewith in response to rotation of the wheel tomove the wheel inwardly to disengage the clutch and subsequently toforce the feeding worin inwardly, a stop formation carried by the shaft,and a cooperating stop formation to prevent outward movement of theshaft and wheel when the feeding worm has been advanced to its innermostposition.

l1. A material feeding mechanism as set forth in claim 1 in which thematerial feeding element is of hollow construction to provide an airpassageway, and in which an operating shaft for an ash conveyor extendsthrough said feeding element and is operatively connected with the powerelement.

12. A material feeding mechanism as set forth in claim 9 in which thefeeding worm is of hollow construction to provide an air passageway, andin which an operating shaft for an ash conveyor extends through saidworm and has a splined connection with the shaft which carries the powerdriven wheel.

JOHN FRANCIS MURPHY.

